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SubjectRe: [PATCH v3 07/16] ntb: add check and comment for link up to mw_count() and mw_get_align()
On Tue, Jul 25, 2017 at 02:57:44PM -0600, Logan Gunthorpe wrote:
> Adds a comment and a check to ntb_mw_get_align() so that it always fails
> if the function is called before the link is up.
>
> Also adds a comment to ntb_mw_count() to note that it may return 0 if
> it is called before the link is up.
>
> This is to prevent accidental mis-use in clients that are testing
> on hardware that this doesn't matter for.
>
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>

Similar to the last one, I think this is also a bug fix. I'll pull it
out, etc. :)

Thanks,
Jon

> ---
> include/linux/ntb.h | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/ntb.h b/include/linux/ntb.h
> index 609e232c00da..47f2966cfd7f 100644
> --- a/include/linux/ntb.h
> +++ b/include/linux/ntb.h
> @@ -730,7 +730,8 @@ static inline int ntb_link_disable(struct ntb_dev *ntb)
> * Hardware and topology may support a different number of memory windows.
> * Moreover different peer devices can support different number of memory
> * windows. Simply speaking this method returns the number of possible inbound
> - * memory windows to share with specified peer device.
> + * memory windows to share with specified peer device. Note: this may return
> + * zero if the link is not up yet.
> *
> * Return: the number of memory windows.
> */
> @@ -751,7 +752,7 @@ static inline int ntb_mw_count(struct ntb_dev *ntb, int pidx)
> * Get the alignments of an inbound memory window with specified index.
> * NULL may be given for any output parameter if the value is not needed.
> * The alignment and size parameters may be used for allocation of proper
> - * shared memory.
> + * shared memory. Note: this must only be called when the link is up.
> *
> * Return: Zero on success, otherwise a negative error number.
> */
> @@ -760,6 +761,9 @@ static inline int ntb_mw_get_align(struct ntb_dev *ntb, int pidx, int widx,
> resource_size_t *size_align,
> resource_size_t *size_max)
> {
> + if (!(ntb_link_is_up(ntb, NULL, NULL) & (1 << pidx)))
> + return -ENOTCONN;
> +
> return ntb->ops->mw_get_align(ntb, pidx, widx, addr_align, size_align,
> size_max);
> }
> --
> 2.11.0
>
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